"In 2001, I tested some of these vests and found them to be substandard. I do not know if the vests from this lot were finally purchased or not," he told PTI.

"But in 2004, another batch of vests was tested by another officer and they too were found to be defective. Most likely, the police officers who died on Wednesday night were wearing these vests," Singh said.

The purchasing is done by the department headed by the joint commissioner of police (administration), Singh said.

"There is a big cartel operating here," Singh, who quit after being fed up with corruption in the police force, said.

Head of Anti-Terrorist Squad Hemant Karkare [Images], encounter specialist Vijay Salasar and additional commissioner of Police Ashok Kamthe died when a terrorist opened fire on the vehicle they were riding in on the night of November 26.

An hour before that, TV channels had shown Karkare putting on a helmet and bullet-proof vest and heading out as the first reports of terror attacks came in.